Ground terminal blocks have been used to link separate wires to the DIN rail by using a metal clamping bar. Ground terminal blocks also link separate wires for ground connection by internal connection, but are not equipped with metal clamps. The main purpose with terminal blocks is to make electrical connections accessible. Terminal blocks have been equipped with a LED or an array of LEDs to show active current, operational status of a device and/or fault mode detection of a device. Ground terminal blocks have been used to connect separate wires to ground internally or through the DIN rail with a metal clamping bar to cause a connected residual current circuit breaker or a ground fault interrupter to trip when fault current is connected to ground. This function protects against electrical shock and damage to appliances or devices. Ground terminal blocks are essential elements in ground connections in panel boards. When ground terminal blocks are used in panel boards the ground wiring is made very accessible and saves time and cost in both assembly and maintenance.
Ground terminal blocks can deliver fault current to a residual current circuit breaker or a ground fault interrupter causing it to trip. However, when the electricity power is out it is impossible to locate the source of the fault current in the panel board. Terminal blocks other than ground terminal blocks have been equipped with a LED to show active current, operational status of a device and fault mode detection of a device but the LED will not be lighted when the power is out also the LED will not indicate either the ground fault current or the source of the fault. When ground fault current occurs and the electrical power goes out it is not possible to turn electrical power back on until the source of the ground fault current has been established and eliminated. This composes a problem because the circuit breaker carrying the fault current will in most cases not trip along with the residual current circuit breaker or ground fault interrupter. Consequently the source of the problem is not accessible since only the residual current circuit breaker or the ground fault interrupter is tripped and electrical power is out. As a result it can be very hard for professionals to track the source and almost impossible for novice to resolve. This can be very time and financially costly even though the source of the problem is not always very serious. In ground fault current situations it can take a professional electrician some time before finding the fault because of the electrical power out. Traditional ground terminal blocks can be very useful during ground fault tracking hence the accessible wire disconnection but traditional ground terminal blocks cannot indicate ground fault current in any way.